Method of producing soluble phosphates.



ED STATES OFFICE.

JOHN WOODS BECKMA TIN, OF NIAGARA FALLS, NEW YORK.

METHOD'OF PRODUGING SOLUBLE rHosrHArns;

-No Drawing. Application filed April 30.

To all whom it may concern:

Be it known that I, JOHN Woons BECK- MAN, a subject of the King of Sweden, residing at Nia ara Falls, in the county of Niagara and tate of New York, have invented a new and useful Improvement in are mixed with a mineral phosphate other than that of an alkali metal in such proportions that substantially chemically'equivalent amounts of potash and phosphoric acid are present in the mixture and are then heated, a reaction takes place in which the potash enters into combination with the phosphoric acid of the phosphate and the metallic component of the phosphate takes the place of the potash in the original salt. In this general formula R O can be any metal oxid, the metal of which is more posltive than S in S O This salt need not be a potash salt, but may be a salt of any of the metals belonging to the alkali metal group, such as sodium, lithium, etc. I may also treat a mixture of such salts to obtaln a product containin a mixture of the alkali metals present. he S O 1n the above formula may be any metal oxid or an oxld compound of a metalloid, as for example, q

'l he mineral employed need not be pure,

available impure phosphate other than that of an alkali metal may be used.

One specific method of carrying out my invention may be described as follows: I take alunite, whose general formula is BK O,

' 3A1,0,, 4SO 6H O and mix the same with tricalcium phosphate I in suitable propor- Specification of Letters Patent.

Patented'Dec. 15,1914. 1913. Serial No. 764,612.

tions, which need not in all cases be limited to the chemical equivalents. I then heat the mixture in a suitable furnace to a red heat or above, the following reaction taking place:'

If the product is then mixed with water, the highly soluble potassium phosphate is dissolved out, and by evaporation can be obtained in a properly pure condition. In a similar manner, I can treat any of the many salts of this general character which are found in the soil.

I have found that for reasons which I do not as yet understand fully, the above stated reaction is often assisted by mixing with the original salts, materials which apparently do not directly partake in the reaction, such as coal, silica and other metal oxids- Chlorids of calcium and sodium also appear to have a beneficial effect on the reaction. The exactquantity of these additions can be best determined experimentally and the particular agent to be employed is determined largely by the particular character of the original salt being treated. In the treatment of alunite, I have obtained good results by the addition of SiO to the amount of 1% of the calcium phosphate used.

The above described reaction gives a phosphate which is soluble in water and which is procured by leaching it out of the insoluble materials obtained in the reaction. It may occasionally be advantageous or desirable to produce a phosphate which is soluble in citric acid or in a mixture of citric acid and water, and this can be obtained by regulating the proportions of the original mixture, using only about one-half the chemical equivalent of the potash salt, but is only fit for application to the soil without prior leaching.

While I am not able to fully explain the above described reactions, as the heat of formation of many of the possible residual compounds after the soluble phosphate has been dissolved out is not lmown; it is neverthe less apparent that the thermal equation is in favor of carrying out the reaction. It is a well known factthat CaO is able to replace K O in many of the complex potash salts present in the soil, especially'if some or all of the Ca is combined in the shape of a salt with a strong negative component. The heat of formation of tricalcium phosphate is lower than the heat of formation of the corresponding potash salt.

My invention provides a simple and comparatively inexpensive method of producing a fertilizer which contains potash in a readily available form, as well as phosphoric acid, in a chemical combination which can be readily assimilated by growing plants and can be easily handled. The material being of comparatively. high concentration, the cost of freight in handling is comparatively small.

I claim:

1. The herein described method of producing a soluble phosphate, which consists in heating a substance containing a nonvolatile alkali metal salt having the general formula R O V K o l substantially as described.

In testimony whereof, I have hereunto set my hand.

JOHN woons BECKMAN.

\Vitnesses SPENCER B. PARKER, ALLEN STEWART. 

